The Worlds of If :

Step into a realm of lost chances and alternate destinies in The Worlds of If by Stanley G. Weinbaum, a masterfully crafted early science fiction short story that explores time travel, parallel realities, and the haunting question of "what if?" When Dixon Wells narrowly avoids a tragic rocket disaster, his former professor's invention—the "subjunctivisor"—offers him a glimpse into the life he might have lived had he made a different choice. As he peers into alternate timelines and rediscovers a fateful encounter with a woman named Joanna Caldwell, Dixon is forced to confront the bittersweet truths of love, fate, and personal responsibility. Weinbaum’s blend of speculative technology and human emotion delivers a timeless meditation on the consequences of missed opportunities.